摘要
HIV is a blood-bome virus transmitted via sexual intercourse orpercutaneous exposure to infected blood, or from an infectedmother to her child during the birth process. Following infection,the time before onset of clinical disease varies from months toyears; the duration is influenced by age (the rate of progressionincreases with age)and HLA type(A1,B8, DR3 are associatedwith rapid progression and B27 with slow progression),but not bygender or risk activity. Although most patients initially have nocharacteristic symptoms,there is usually(90%)a gradual declinein immune function.
